Hi,

try BOE (Buffered Oxide Etch). Do not forget to protect the polished side.
:-)

Also, there is some info and suggestions here

http://en.wikibooks.org/wiki/Microtechnology/Etching_Processes#Silicon_Oxide_Etc
h_.28HF.2C_BHF.2C_BOE.29

Regards,

M.Sc. Denis Petrov
Production engineer

MEMS Foundry Itzehoe GmbH,
Fraunhoferstrasse 1,
25524 Itzehoe
Germany

Phone: +49 (4821) 17 45 54
Fax: +49 (4821) 17 42 50
e-mail: denis.petrov@memsfoundry.com


2011/2/14 Babis 

> Hey, All
>
> I have recently purchased Thermal Oxide Si (Highly doped) wafers in order
> to prepare Organic TFT samples. However the wafers are double side deposited
> with SiO2. In order to make contact on the un-polished side, I suppose I
> have to etch SiO2. What methods do you propose for that purpose. Is there
> anything to watch out in order to achieve better results?
>
> Thank you in advance!